1. Field of the Invention
This invention relates to disinfecting contact lenses and, more particularly, relates to a method and apparatus for disinfecting contact lenses using microwave energy.
2. Description of Background Art
During the normal course of wearing contact lenses, various debris, organic matter, and microorganisms have a tendency to deposit and/or build up on lens surfaces. Contact lenses, especially those made from hydrophilic materials, must be continuously disinfected to kill any harmful microorganisms that may be present on or grow on the lenses. If the harmful microorganisms are not controlled, corneal infections are a possibility.
Accordingly, a number of methods for disinfecting contact lenses have been used such as the use of elevated temperatures, oxidative chemicals and antimicrobial agents. This invention disinfects through the use of elevated temperatures.
Heat disinfection typically involves inserting the lenses in an electrical device which uses electrical energy to obtain the thermal energy necessary to elevate the temperature of the disinfection fluid. These devices typically employ temperatures of about 70.degree. C. to 90.degree. C. and requires operating cycles from about 20 to 60 minutes. Thus, due to the long period required for heat disinfecting, a shorter more convenient process for heat disinfecting contact lenses is highly desirable.
The desirability of using microwave energy for heat disinfecting contact lenses has been previously discussed. In fact, one patent discloses a technique for disinfecting contact lenses in microwave ovens. U.S. Pat. No. 4,671,935 discloses a method and apparatus for sterilizing contact lenses when the lenses are moved in a circular orbit within a microwave oven with the orbit movement being spaced from the floor of the oven. However, this patent does not employ a disinfecting solution.
Other patents disclose various apparatus used for heating water in microwave ovens for various purposes. For example, U.S. Pat. No. 4,400,357 discloses a device for sterilizing medical and dental objects. U.S. Pat. No. 4,642,443 discloses an apparatus for brewing coffee in microwave ovens. Last, U.S. Pat. No. 4,386,109 discloses a microwave expresso coffee maker. However, none of the aforementioned patents have the same requirements of the present invention and thereby can employ devices which are unsuitable for disinfecting contact lenses. More specifically, none of the aforementioned patents require maintaining the disinfecting temperature for a time sufficient to disinfect while protecting the object to be disinfected from degradation or destruction by microwaves.
Accordingly, the present invention provides a convenient method and apparatus for disinfecting contact lenses using microwave energy. Further, the present invention provides for a short disinfecting period which is more convenient for the contact lens wearer and thereby promotes better contact lens care compliance.